With the demands of daily living, vacuum container is becoming more and more important to people's daily life. The existing vacuum containers include vacuum cup, vacuum jug, etc. Take a vacuum jug as an example, a vacuum jug available comprises an outer container and an inner container which is arranged inside of the outer container and used for filling liquid, the outer wall of the inner container is separated from the inner wall of the outer container, and the top of the inner container is hermetically connected with the top of the outer container, the opening of the vacuum jug where the outer container and the inner container are hermetically connected is formed at the top of the vacuum jug. A sealing fin is aligned with and welded to the bottom edge of the outer container of the vacuum jug in argon arc welding manner, the air between the inner container and the outer container is removed to form vacuum in order to ensure the heat preservation property effectively.
However, a welding part is formed while welding the sealing fin and the outer container, and it will influence the appearance of the vacuum jug. There are two solutions used in the prior art to cover the welding part so as to avoid the influence on the entire vacuum jug exerted by the welding part.
Solution 1: as illustrated in FIG. 1, an outer bottom cap 4 covering the welding part 6 is fixed at the bottom of the vacuum jug; since the welding part 6 is formed by argon arc welding between the sealing fin 3 and the bottom edge of the outer container 1 at the bottom of the vacuum jug in order to achieve heat preservation and seal between the outer container 1 and the inner container 2, fine leak may occur at the previous welding part due to the high temperature while welding once again by argon arc welding along the bottom edge of the outer container 1, thus resulting in disappearance of the vacuum area between the outer container 1 and the inner container 2, and the vacuum jug loses its heat preservation function. The outer bottom cap has to be fixed at the bottom of the vacuum jug by other ways, such as bonding with glue, connection by screws.
Solution 2: a non-slip mat covering the welding part is fixed at the bottom of the vacuum jug with glue.
However, as illustrated in FIG. 1, an interlayer 5 is provided between the bottom cap 4 and the outer container 1 of the vacuum jug in order to achieve fixation. Since an interlayer 5 exists between the outer container 1 and the bottom cap 4, there is a risk that the bottom cap 4 may drop out in case the connection at the position of the interlayer 5 becomes loose, resulting in incompleteness of the vacuum jug and inconvenience use due to the exposure of the welding part. More specially, it is easy for water to permeate into the welding part when the vacuum jug is washed, and this will cause inconvenient to users, and deteriorate the compactness and the strength of the connection between the vacuum jug and the outer bottom cap.